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Question about motor outputs
« on: May 14, 2012, 12:32:14 AM »
What does "step low active" and "dir low active" mean? What does it do? I cant seem to find this information anywhere except where people suggest you click one or the other. Im curious as to what they do and how they affect the system. Thanks.

Offline Tweakie.CNC

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Re: Question about motor outputs
« Reply #1 on: May 14, 2012, 06:25:41 AM »
Hi SD,

If you imagine a square wave - active low will step (a little while after) the transition from the high point of the waveform to the low point of the waveform whereas active high will step (a little while after) the transition from the low point of the waveform to the high point of the waveform.
It is a preference of some driver chips to only operate reliably when this is set correctly (if they expect to see an active low input then this is what should be used).

Tweakie.
Success consists of going from failure to failure without loss of enthusiasm.  Winston Churchill.

Offline Hood

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Re: Question about motor outputs
« Reply #2 on: May 14, 2012, 06:51:40 AM »
Just to add to the above by Tweakie, the Dir active state only has the effect of reversing the motor direction so it is not important which you use as long as your motors are going the right direction with the setting you have.
Hood